1. Field of the Invention
The present invention relates to improved artificial diets or growth media for rearing arthropods, including zoophagous arthropods and phytophagous arthropods including facultatively zoophagous phytophages. The growth media of the invention are suitable for mass production of these insects at a reasonable cost for uses including as biological control agents.
2. Description of the Art
The phylum Arthropoda includes insects and arachnids. Within this phylum are zoophagous arthropods (those that eat animal materials), phytophagous arthropods (plant-eating arthropods), and facultatively entomophagous phytophages (plant-eating arthropods that display some animal material consumption in addition to eating plants).
In the United States and throughout the world, the application of synthetic chemical insecticides is the primary method of controlling arthropod pests of many agricultural commodities, including food, fiber, and ornamental crops. However, there is an increasing interest in reducing the use of chemical pesticides and fertilizers and to make agriculture more sustainable. Biological control is recognized as the best alternative to the use of chemical insecticides for controlling these pests.
Use of beneficial arthropod predators and parasites for biological control on a large scale as an alternative to pesticides depends on the ability to mass produce large quantities of viable and biologically fit arthropods at a reasonable cost. However, rearing of beneficial arthropods on their natural hosts/prey or on unnatural factitious hosts is too expensive to allow large scale use of beneficial arthropods in commercial agriculture. Accordingly, artificial diets or growth media are required for mass production at reasonable cost.
The phylum also includes destructive arthropods. For example, the western tarnished plant bug, Lygus hesperus Knight (Hemiptera: Miridae) and tarnished plant bug, Lygus lineolaris (Palisot de Beauvois) are very destructive pests, and their economic impact spans several cropping systems in North America (Hedlund and Graham, USDA Technical Bulletin ARS-64, 1987). Their impact is amplified by their remarkable ability to become resistant to pesticides and by their extremely broad host range (Hedlund and Graham, supra). Therefore, potential alternatives to conventional pesticides to control these pests have become very important. Such alternatives include development of biological control, biorational chemicals, plant breeding, sterile insect release, and genetic engineering. Development of management strategies based on these approaches would depend upon rearing systems that permit medium to large scale rearing of arthropod pests. A major component necessary for such rearing includes an inexpensive, high quality artificial diet that can be used to rear thousands to millions of the targeted pest (Cohen et al. 1999, Biocontrol News and Information, (accepted June, 1999); Nordlund, Biocontrol News and Information 17(2): 35-44,1999; Nordlund and Greenberg, Biocontrol News and Information 4:45-50, 1994).
A liquid diet for rearing Lygus hesperus which includes whole raw eggs was described by J. W. Debolt, Annals of the Entomological Society of America 75:119-122 (1982). The diet has been used successfully in rearing L. hesperus that were used for rearing both egg and nymphal parasitoids (Debolt, U.S. Dept. Agric. Res. Serv. (ARS-64), pages 82-87, 1987; Debolt, Entomol. Exp. Appl. 50:87-95, 1989). S. A. Hassan and K. S. Hagen, Zeitschrift fur Angewandte Entomologie, 86:315-320 (1978) describe liquid diets for rearing lacewings, Chrysopa rufilabris Stephens, larvae. Semi-solid meat-based artificial diets have been described for rearing Geocoris punctipes (Say) in publications by A. C. Cohen, Journal of Economic Entomology, 78:1173-1175 (1985); A. C. Cohen and N. M. Urias, The Southwestern Entomologist, 11:171-176 (1986); and A. C. Cohen and R. T. Staten in Applications of Genetics to Arthropods of Biological Control Significance, Eds. S. K. Narang et al., CRC Press, Inc., Chapter 7, pp. 121-132 (1994)). De Clercq et al. (Entomophaga 37:149-157 (1992)) describe an artificial insect diet for rearing the predatory stinkbugs Podisus maculiventris and Podisus sagitta using the meat-based diet of Cohen (1985) with added fresh (raw, liquid) egg yolk. Saavedra et al. (Med Fac Landbouww Univ Gent 61(3a):767-772 (1996) describe an artificial insect diet for Podisus nigrispinus based on the bovine meat diet developed by Cohen (1985, supra) having added bee's honey, brewer's yeast, fresh egg yolk, and Wesson's salt. An artificial meat paste-based diet containing cooked whole egg, which has been found suitable for mass rearing entomophages (predatory arthropods and parasitic insects) including big-eyed bugs, Geocoris punctipes, and lacewings, Chrysoperla rufilabris, has been described (A .C. Cohen, U.S. Pat. No. 5,834,177). Use of this meat paste-cooked egg diet was also found useful as a supplement for artificial diets for phytophagous pests that are known to supplement their plant-eating habits with some insect consumption (A. C. Cohen, U.S. Pat. No. 5,945,271).